Plaid, the fintech company that is in the process of being acquired by Visa for $5.3 billion, is launching Plaid Exchange this week. Plaid is mostly known for its range of APIs that let developers access banking information. This time, with Plaid Exchange, the company wants to help financial institutions directly so that they can build and maintain an API that other developers can use. An API is an interface that lets two services interact with each other. If you’ve used Venmo, Betterment, Square’s Cash App or Robinhood, chances are…